Terminal connecting device



Patented'ca 23,

y u-NlTED1-sjr-fras 1,688.640' PATENT OFFICEQ f msn. nnvm, or oonunnns; OHIO, AssIeNon'ro @HE .TnrrnErnANU-Acrnnmc courm, or COLUMBUS, onro, A CORPORATION Oromo.

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Application led April 19, 1921 Serial No. 462,725,

' The present invention relates to certain new and useful 'improvements 'in terminal connecting devices adapted to connect the r conductors of electric circuits. v

5 The use of electrical apparatus in coal mines is accompanied by more or less .danger of explosion arising from the possibilit of the ignition of the as charged atmosp ere of the mine by the e ectricarcs occurring at io contact points of the.apparatus,o1 by the iashes produced Vby accidental short c1rcuiting the conductors of thecircuits. To`

reduce this explosion hazard to a minimum,

explosion proof casings have been devised forthe motors, switches, and similar devices the normal Operation of which 'is accompanied by the production of electric arcs, and the conductors extending from one such protected device to another are encased in the customary electric insulations to which 1s added an armor com osed of vmetal .or other H suitable, material o approved mechanical strength. The especial object of this invention is to provide a conveniently detachable connecting device adapted. to connect the conductors of the external' circuit with the conductors of the circuit within an explosion proof casing, combined with means for insuring `the electrical insulation v and mechanical protec-l tion of said connecting devices. I

The means by which I attain this object are fully set forth-in the following speci cation and illustratedin the accompanying drawings of which Fig. 1 is a sectional view taken along the central longitudinal .plane of the preferred embodiment of my invention.

the linefII--Ilof Fi 1.

Like numeralsfrre er to similar parte in both figures.l

In the drawing the numeral 1 indicates fa portion of the wall of the ex losi n proof v casingof an electricmotor a apted. to use 4 The outer end of the conductor 2-is attached,

jwhat larger-diameter than the co in any preferred manner such as by soldering, to one end of a twopart connecter 5, the parts of which are secured together in anypreferred' manner such as by the machine screws 6. To the opposite end of the oonnecter15 -is attached the conductor 7 of the external circuit. The .conductor 7 is pro' tected by the usual electrical insulation 8 which in turn is protected -by the lexible metal conduit 9of well known construction 65.V

-which may be securely attached to the metallic frame of the machine .in any preferred manner.

jThe aperture 3 of the motor casin is counterbored at 10 and in this counter ore 70 is screw threaded a tubular shield ,1 of some` ecter 5. The outer end 12 of the shield 11 is contraotedto fit' snugly' around the iiexible metallic conduit 9 to the end of which is soldered, or otherwise secured, a ring 13v arranged to engage theinner faceof the contraction-12 to prevent accidental separation of the conduit 9 and the shield 11. Space ing washers 14, formed of ber or other suit= able insulating material, and having an yexternal diameter approximately equal to the internal diameter of the shield 11, are fitted snugly upon the insulations 4 and 8 in close proximity to the endsA of the connecter 5 to insure its central position within the shield. The connecter 5 is further protected by an insulation 15, vformed' of friction tape or other suitable material, to guard against possible short circuit between the connecter 5 and' the shield 11.

By the arrangement of parts just described the `iiexible metallic conduit 9 is securely Fig. 2 is a cross sectional view takenalong the'machine.

` What I claim is:

1. In aconduit for electric wires, the combination of a casing, a conductor projecting therefrom, a tubular metallic shieldfixed 'to said casing and surrounding said conductor, 105

an armor-sheathed conductor d etachablyv connected to said first conductor within said shield, thel free end ,of said shield being' f 1 in the manner well understood in the art.V

closed about said second conductor, a ring' xed to the armor-sheathing of' said secondV iw tending beyond the periphery of said con- .ductors for maintaining their zone of juncture in spaced relation to the inner Walls ofv said shield.

2. In a conduit for electric Wires, the combination of a casing, a conductor projecting therefrom, a tubular metallic shield fixed to said casing and surrounding said conductor, an armor-sheathed conductor detachably connected to said rst conductor Within said *t shield, the reeend of said shield being' closed about said second conductor,v a rin fixed to the armor-sheathing of said 'secon conductor Within said shield and abutting the internal shoulder formed by the closed end of the latter, and insulating annuli surround .ing the conductors Within the shield and` at either end thereof for maintaining the zone of juncture of said conductors in spaced relation to said shield.`

In testimony whereof, I aix my signature.

ILS D. LiaiVIN. 

